1. Field of the Invention
The present invention relates to a structure of a terminal apparatus as a portable telephone and a cordless telephone.
2. Description of the Prior Art
An ultimate object of communication is, of course, to enable intention or information to be transmitted or exchanged at once anytime, from anywhere, and by anybody. In addition to a conventional intercommunication between fixed points, a mobile communication has been gradually developed. The mobile communication means a communication between a mobile body such as ship, automobile, or airplane (including a human being) and a fixed point such as home or office, and also means an intercommunication between two mobile bodies. In recent years, a portable telephone or a cordless telephone as a kind of means for carrying out the mobile communication has been extensively developed.
The portable telephone is provided with a switch section having a dialing function. It is desired that a plurality of key tops provided in the switch section can be illuminated in consideration of use in the dark. It would be advantageous from the viewpoints of power saving and compactness to uniformly illuminate a plurality of key tops by means of a small number of light sources.
As a technique for illuminating a plurality of key tops by means of a small number of light sources, it is known in the art that a light guiding board for back lighting is provided independently of a telephone case, and light from the light sources is supplied through this light guiding board to the plurality of key tops.
However, in the conventional structure employing the light guiding board for back lighting, it is necessary to mount the transparent light guiding board on the telephone case independently thereof. It is therefore inconvenient especially in the portable telephone required to have a thin construction.